Flexible cable comprises printed circuits and/or flat multi conductor cables wherein the conductive circuit is formed on either or both sides of a flexible sheet or film of insulating material. There are a number of methods which are generally known for connecting the conductive strips of such a flexible cable for use in the situation in which interfaces with printed circuit boards are appropriate. Reference is made to page 102 of "Printed Circuit, Design and Drafting" by J. S. Cook II (TAD Institute, Cambridge, Mass., Published in 1967 by Associated Designers, Inc.) wherein three basic methods for making such connections are described. They are (1) a wire lead, (2) a flared eyelet, and (3) a plated through hole.
Wire lead connections remain widely used and consist of direct soldering of the lead to the cable conductor. As can readily be seen, the substrate is exposed to substantial heat and resultant deformation of the circuit can easily occur.
The flared eyelet is an improvement on the foregoing, and a reliable interconnection is normally achieved. However, this method uses an eyelet made of silver having a unique structure. This increases the cost and diminishes the productivity of the final product.
A plated through hole is an extremely desirable form of interconnection, especially between two circuit patterns which are formed on both sides of an insulating substrate. In present day electronic packaging practice, especially for a high density electronic device where signal circuits predominate in the package, the plated through hole system is virtually essential for suitable interconnection.
U.S. Pat. Nos. 4,429,303 and 4,249,304 (both to Weinmann, et al) describe connectors of this general type. In '303, there is set forth a method for connection of flat cables which selects the connection zone by reference to a matrix of connection zones provided by placing one flat cable on top of the other. In '304, there is found a method of connecting such cables through perforations in the overlapping cable portions followed by insertion of a connector through the perforation. This is followed by electrically connecting the connector to each of the overlapping conductors. Since the conductor is inserted through an opening, there is no need to provide it with a sharp edge or make it strong enough to pierce the conductors and/or the substrates.
U.S. Pat. No. 3,395,381 (Huffnagle) describes a crimpable U-shaped connecting device. In accordance with that reference, the conductor is pinched between the lances and the edges of the inwardly bent side walls.